What is the recommended dose of Augmentin (amoxicillin-clavulanate) for a 9-year-old child weighing 108 pounds?

Augmentin Dosing for a 9-Year-Old Weighing 108 lbs

For a 9-year-old child weighing 108 pounds (49 kg), prescribe Augmentin according to adult dosing recommendations: 875 mg/125 mg every 12 hours for more severe infections or respiratory tract infections, or 500 mg/125 mg every 8 hours as an alternative. 1

Weight-Based Dosing Threshold

• This child exceeds the 40 kg threshold (108 lbs = 49 kg), which is the critical cutoff point where pediatric patients transition to adult dosing regimens 1
• The FDA label explicitly states: "Pediatric patients weighing 40 kg or more should be dosed according to adult recommendations" 1
• The 250 mg/125 mg tablets should not be used until the child weighs at least 40 kg due to different amoxicillin-to-clavulanic acid ratios 1

Specific Dosing Recommendations by Indication

For Respiratory Tract Infections (More Severe)

• Preferred regimen: 875 mg/125 mg tablet every 12 hours 1
• Alternative regimen: 500 mg/125 mg tablet every 8 hours 1
• For beta-lactamase producing Haemophilus influenzae, use the amoxicillin component at 45 mg/kg/day in 3 doses or 90 mg/kg/day in 2 doses 2

For Less Severe Infections

• Standard regimen: 500 mg/125 mg tablet every 12 hours 1
• This provides adequate coverage for most community-acquired infections in this weight category 1

Important Clinical Caveats

Formulation Considerations

• Do not substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet - they contain the same amount of clavulanic acid (125 mg) but different amounts of amoxicillin, making them non-equivalent 1
• The 250 mg/125 mg tablet and 250 mg/62.5 mg chewable tablet are not interchangeable due to different clavulanic acid content 1
• If the child has difficulty swallowing tablets, the 400 mg/57 mg per 5 mL suspension can substitute for the 875 mg/125 mg tablet 1

Duration of Therapy

• For acute otitis media, the recommended and studied duration is 10 days 1
• For community-acquired pneumonia, treatment courses of 10 days have been best studied, though shorter courses may be effective for milder disease 2

Renal Function Monitoring

• No dose adjustment is needed unless renal impairment is present 1
• If glomerular filtration rate is <30 mL/min, avoid the 875 mg/125 mg dose 1

Rationale for Adult Dosing in This Patient

The transition to adult dosing at 40 kg is based on pharmacokinetic principles and the fixed-ratio formulations of Augmentin 1. At 49 kg, this child has sufficient body mass and renal clearance capacity to handle adult doses safely 1. The every-12-hour regimen is preferred as it is associated with significantly less diarrhea compared to every-8-hour dosing 1.